The technical field of this invention is the topical application of personal care agents and, in particular, methods and compositions for topical application of agents to repel insects and other arthropods.
In recent years the public has become increasingly aware that the bites of insects and arachnids is not only a severe nuisance in certain seasons and regions, it can also carry a life-threatening risk of infection with such illnesses as Lyme disease and equine encephalitis. (The term "insect" is used herein to encompass insects, ticks, arachnids and other nuisance or harmful arthropods, generally.)
One of the most effective first lines of defense against such bites, and one which causes little stress to environmentally beneficial arthropods, is the use of chemical repellents. A variety of repellents of diverse effectiveness have been used over the years, including such materials as citronella; safe and effective repellents in current use include N,N-diethyl-m-toluamide (DEET) and 2-ethyl-1,3-hexanediol (6-12)
Compositions useful as insect repellents should disperse easily onto the skin, adhere closely to the skin, resist penetration through the skin, and resist shedding with perspiration or rain. Unfortunately most insect repellents do not fully satisfy these requirements in terms of durability and prolonged residence on the skin. For example, DEET, used alone or compounded with common cosmetic extenders, gradually penetrates into deep layers of the skin where its insect-repelling activity is reduced.
There exists a need for better insect repellent compositions for more economical and reliable protection against the distress and danger of insect bites, tick bites and the bites of other arthropods.